In recent years, mobile terminal devices such as mobile phones have adopted folding structure or the like to improve their portability. Dividing a case of a mobile terminal device into two and connecting the resulting two cases with a hinge openable and closable relative to each other gives the mobile terminal device both convenience when in use and portability when not in use.
Nowadays, mobile terminal devices have many functions, and mobile terminal devices with a camera function and a broadcast single receiver function for receiving 1Seg, ATSC-M/H or similar broadcast signals are increasing. Some of such mobile terminal devices have, in view of user-friendliness, a display-side case having a display portion and are rotatable to various angles. For example, a mobile terminal device illustrated in FIG. 5 has a rotation biaxial hinge structure.
FIG. 5 is a plan view illustrating a case and a hinge portion of a mobile terminal device. In the mobile terminal device illustrated in FIG. 5, a display-side case 10 is openably and closably connected to an operation-side case having operation portions such as keys (not illustrated) by a hinge portion 20. Rotation base portions 21 forming the hinge portion 20 are fixed to the operation-side case (not illustrated). A rotation portion 22 forming the hinge portion 20 rotates relative to the rotation base portions 21 about an axis of rotation parallel to the lateral direction of the display-side case 10. With this rotation, the display-side case 10 supported by the rotation portion 22 opens and closes relative to the operation-side case (not illustrated).
The hinge portion 20 has a rotation biaxial hinge, and therefore the display-side case 10 is supported by the rotation portion 22 rotatably about an axis of rotation parallel to the longitudinal direction. By rotating the display-side case 10 about the axis of rotation parallel to the longitudinal direction, the display portion provided on the back of the outer panel 11 illustrated in FIG. 5 may be exposed on the outside. Reversing the display-side case 10 with the display-side case 10 and the operation-side case (not illustrated) in the open state and then bringing the display-side case 10 and the operation-side case into the closed state enables the user to look at a screen displayed on the display portion in the closed state.
There are other mobile terminal devices that have a structure of a cycloid type, a swing type, or the like and in which a case divided into two are openable and closable and the display-side case is rotatable. For example, in a mobile terminal device disclosed in Japanese Laid-open Patent Publication No. 2008-153861, the display-side case is rotatable about an axis of rotation parallel to the thickness direction of the mobile terminal device. Therefore, the operation in a state where the display-side case and the operation-side case are open may be facilitated, and the visibility of the display portion may be improved.
However, in a mobile terminal device wherein one of the cases is rotatable, the mechanism for rotating the case is complex, and therefore the improvement of aesthetic properties is sometimes limited. For example, the mobile terminal device having a rotation biaxial hinge structure illustrated in FIG. 5 has such an appearance that the display-side case 10 and the hinge portion 20 are completely separated. For this reason, the gap between the display-side case 10 and the hinge portion 20 is noticeable, and the aesthetic properties of the mobile terminal device are marred.
Specifically, the rotation base portions 21 are fixed to the operation-side case (not illustrated), whereas the display-side case 10 is attached rotatably about two axes, and therefore the gap between the rotation base portions 21 and the display-side case 10 tends to be large.